Validity of International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) screening for...

Sepsis is among the leading causes of death in the United States. The Agency for Healthcare Research and Quality uses International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) billing code screening for the identification of sepsis. We investigated the incidence of sepsis in mortality at our academic medical center through ICD-9-CM screening of billing codes corresponding to sepsis and compared this approach for accuracy using physician chart review as the gold-standard.

Two hundred forty-three surgical mortalities between January 2012 and January 2013 were reviewed by a Performance Improvement team. All mortalities were screened and evaluated for sepsis using physician chart review and ICD-9-CM codes for sepsis (995.91), severe sepsis (995.92), and septic shock (785.52).

Unexpected mortalities were associated with higher rates of sepsis and expected mortalities than anticipated (p<0.0001). A total of 40.6% of patients with sepsis suffered from more than one infection; the most common infectious sources were intra-abdominal (43.5%), blood stream (40.3%), and pulmonary (38.7%) infections. Screening by ICD-9-CM identified sepsis in 23.0% of mortalities, and physician review identified sepsis in 25.5% of mortalities. The sensitivity and specificity of ICD-9-CM screening were 82.3% and 78.3%, respectively. The positive and negative predictive values were 91.1% and 62.1%, respectively.

Sepsis is a common concurrent condition in surgical patients who die unexpectedly. Screening by ICD-9-CM for sepsis is accurate in identifying patients with sepsis but misses the identification of all patients with sepsis. The diagnostic accuracy of ICD-9-CM screening for sepsis is currently not adequate for public reporting or benchmarking, and is useful only as a guide for institutional quality improvement.